A network interface device permits a subscriber to access a network. A passive optical network (PON) is an example of a network capable of delivering voice, video and other data among multiple network subscribers, using a common optical fiber link. Passive optical splitters and combiners enable multiple optical network terminals (ONTs) to share the optical fiber link. In a PON, each ONT terminates the optical fiber link for a residential or business subscriber, and is sometimes referred to as a subscriber premises node that delivers Fiber to the Premises (FTTP) services.
An ONT is connected to one or more subscriber devices, such as televisions, set-top boxes, telephones, computers, or network appliances, which ultimately receive the voice, video and data delivered vii the PON. An ONT is an example of a network interface, device. Other examples of a network interface device, in different network types, include cable modems and digital subscriber line (DSL) boxes.
Generally, a network also includes a network access interface. In a PON, the network access interface is sometimes referred to as an optical line terminator (OLT), having multiple, independent PON interface modules that serve multiple optical fiber links. A PON interface module provides an interface for transmission and reception of data packets over a particular optical fiber link that serves a group of ONTs. A PON is a downstream-multicast medium. Each packet transmitted on an optical fiber link can be received by every ONT served by that link. ONTs identify selected packets or frames on the fiber link based on addressing information included within the packets or frames.
Network equipment, such as network interface devices, in a cable or hybrid network may be connected to power provided by a central office (CO), which commonly utilizes battery and generator back-up power to maintain a continuous power supply. In contrast, an ONT in an all-fiber optic network is ordinarily powered locally at the subscriber premises. For this reason, an ONT often includes a battery to provide backup power during a power outage to maintain critical services, such as voice service.
Conventionally, the fibre of a PON typically terminates at a street cabinet to be shared by a number of subscriber equipment. The street cabinet houses an optical network terminal (ONT). The last few meters or kilometer from the street cabinet to a subscriber's home is typically bridged using existing twisted pair copper cables or radio links. The bandwidth resources of the fibre to the street cabinet are typically shared amongst a group of subscribers using an Ethernet switch. For example the fibre may extend to a street cabinet, a kerb outside a subscribers home, or directly into the subscribers home itself. Due to the bulkiness, size and complexity of the ONT cabinets are all factors that increase design difficulty and accrue additional costs. Also, the ONT itself is valuable, and its mounting on a wall, especially outside, makes it susceptible to theft or to being accidentally knocked down.
Therefore, it would be desirable to have a compact optical network terminal to make passive optical networks seamlessly connected to regular computers and any other systems to overcome the above restrictions.